Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy from wind using known foil principles and transmit the kinetic energy through rotational energy to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
During the operation of a wind turbine, each rotor blade is subjected to deflection and/or twisting due to the aerodynamic wind loads acting on the blade, which results in various reaction loads being transmitted through the blade root and into the wind turbine hub via the root bolts coupled between the blade root and the hub. For example, fatigue loads are often transmitted through the blade root along an edgewise direction of the rotor blade while highest extreme blade bending loads are often transmitted through the blade root along a flapwise direction of the rotor blade. As a result, the bolts located along the edgewise portions of the blade root are subjected to different load conditions than the bolts located along the flapwise portions of the blade root. However, conventional rotor blades typically include bolts installed at the blade root that have uniform/constant bolt parameters (e.g., constant bolt diameters and constant circumferential spacing around the blade root). As such, the blade root/bolts must be overdesigned to accommodate the differing load conditions experienced around the circumference of the blade root.
Accordingly, a rotor blade including bolts having one or more bolt parameters that are specifically tailored to accommodate the differing load conditions experienced around the circumference of the blade root would be welcomed in the technology.